What is the greatest common factor of $5$ and $4$ ? Another way to say this is: $\operatorname{gcf}(5, 4) = {?}$
The greatest common factor is the largest number that is a factor of both $5$ and $4$ The factors of $5$ are $1$ and $5$ The factors of $4$ are $1$ $2$ , and $4$ Thus, the greatest common factor of $5$ and $4$ is $1$. $\operatorname{gcf}(5, 4) = 1$